The effect of hypochlorous acid inhalation on the activity of antioxidant system enzymes in rats of different ages.

Hypochlorous acid HOCl is an effective disinfectant with a broad spectrum and high rate of microbicidal action. Its use for air treatment can be an effective tool for the prevention and therapy of infectious diseases. In this work, the in vivo study was conducted on 110 Wistar Han rats (12 and 72 weeks old) on the effect of a single inhalation of air containing gaseous HOCl on the activity of antioxidant system enzymes. For this, a special installation was designed to uniformly maintain the concentration of HOCl in the air and regulate it over a wide range. Inhalation exposure was carried out for 4 h at total chlorine concentrations in the air of approximately 2.0 mg/m3 and 5.0 mg/m3, after which the animals were observed for 14 days. The effect of inhalation on the antioxidant system activity varied significantly in animals of different ages. Catalase activity in young rats increased approximately 2-fold on days 1-2 after inhalation, regardless of the HOCl concentration, while in old animals a sharp dose-dependent decrease was initially observed. The glutathione peroxidase activity in animals of both ages increased upon inhalation of air with 5.0 mg/m3 HOCl, and in old animals this was more pronounced; when the HOCl concentration decreased to 2.0 mg/m3, this indicator increased slightly in old rats and remained virtually unchanged in young ones. The glutathione reductase activity when exposed to 2.0 mg/m3 HOCl did not change for both age groups, and with increasing HOCl concentration it increased by 1.5-2.0 times in all animals.

Acute inhalation toxicity of aerosolized electrochemically generated solution of sodium hypochlorite.

OBJECTIVE: The objective was to determine the inhalation toxicity of the electrochemically generated sodium hypochlorite solution after its single administration to laboratory animals in the form of a highly dispersed aerosol. MATERIALS AND METHODS: The study has been conducted according to the OECD Test Guideline №403 'Acute Inhalation Toxicity.' Laboratory animals were exposed to inhalation of an aerosol containing 1.7 ± 0.13 mg/m3 of active chlorine. The hematological and biochemical parameters of the blood of experimental animals have been determined, as well as specific parameters: the activity of cathepsins B and L, catalase, and α1-antitrypsin. Histological study of the lungs of animals has been carried out. RESULTS: During inhalation and 14 days after it, no death of the animals was observed; the behavior, appearance, and weight gain did not differ from the control group. There were no significant deviations in hematological parameters, except the decrease in the level of platelets. The biochemical study showed slight changes in the activity of alkaline phosphatase and aspartate aminotransferase on the 1st day after inhalation; these parameters returned to normal within 14 days of observation. Specific biochemical parameters did not show the development of oxidative stress. No specific histological pathologies of lung tissue have been found. CONCLUSIONS: Thus, the studied electrochemically generated sodium hypochlorite solution under single inhalation exposure in aerosol form practically does not cause a toxic effect. The data obtained allow classifying such solution to the 4th (or even 5th - after additional studies) class of toxicity in accordance with Globally Harmonized System of Classification and Labeling of Chemicals.